Pedestrian warning system providing adjustable acoustic indications

ABSTRACT

Systems and methods are disclosed for a pedestrian warning system. An example disclosed method to simulate noise for an electric or noise-dampened vehicle to warning pedestrians includes producing a first sound at a first frequency range from a first sound generator located at a front of the vehicle. The method also includes producing a second sound at a second frequency range from a second sound generator located under the vehicle. Additionally, the example method includes adjusting the acoustic characteristics of the first and second sounds based on vehicle motion data.

TECHNICAL FIELD

The present disclosure generally relates to vehicle sound systems and,more specifically, a pedestrian warning system.

BACKGROUND

Electric motors in electric vehicles are very quiet compared tocombustion engines in traditional fuel-based vehicles. Additionally, asexhaust systems of the traditional vehicles improve and idle stop-startsystems become more widespread, these traditional vehicles are becomingquieter. Often, quiet vehicles are not recognized by pedestrians wherevehicles and people are in close proximity.

SUMMARY

The appended claims define this application. The present disclosuresummarizes aspects of the embodiments and should not be used to limitthe claims. Other implementations are contemplated in accordance withthe techniques described herein, as will be apparent to one havingordinary skill in the art upon examination of the following drawings anddetailed description, and these implementations are intended to bewithin the scope of this application.

An example disclosed method to simulate noise for an electric ornoise-dampened vehicle to warning pedestrians includes producing a firstsound at a first frequency range from a first sound generator located ata front of the vehicle. The method also includes producing a secondsound at a second frequency range from a second sound generator locatedunder the vehicle. Additionally, the example method includes adjustingthe acoustic characteristics of the first and second sounds based onvehicle motion data.

An example apparatus to simulate noise for a vehicle includes a firstsound generator positioned at a front of the vehicle, a second soundgenerator positioned under the vehicle; and a sound controller. Theexample sound controller is to produce a first sound from the firstsound generator and produce a second sound from the second soundgenerator. The example sound controller is also to adjust the acousticcharacteristics of the first and second sounds based on vehicle motiondata.

An tangible computer readable medium comprising instructions that, whenexecuted, cause a vehicle to produce a first sound at a first frequencyrange from a first sound generator located at a front of the vehicle.The example instruction, when executed, also cause the vehicle toproduce a second sound at a second frequency range from a second soundgenerator located under the vehicle. Additionally, the exampleinstruction, when executed, cause the vehicle to adjust the acousticcharacteristics of the first and second sounds based on vehicle motiondata.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, reference may be made toembodiments shown in the following drawings. The components in thedrawings are not necessarily to scale and related elements may beomitted, or in some instances proportions may have been exaggerated, soas to emphasize and clearly illustrate the novel features describedherein. In addition, system components can be variously arranged, asknown in the art. Further, in the drawings, like reference numeralsdesignate corresponding parts throughout the several views.

FIG. 1 is a system diagram with a vehicle operating in accordance withthe teachings of this disclosure.

FIG. 2 is a block diagram of electrical components of the vehicle ofFIG. 1.

FIG. 3 illustrates an example sound generator of FIG. 1.

FIG. 4 is a flowchart of an example method to generate sounds to warnpedestrians.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

While the invention may be embodied in various forms, there are shown inthe drawings, and will hereinafter be described, some exemplary andnon-limiting embodiments, with the understanding that the presentdisclosure is to be considered an exemplification of the invention andis not intended to limit the invention to the specific embodimentsillustrated.

Pedestrians use noise emitted by a vehicle to make judgments in areaswhere vehicles and people are in close proximity (e.g., crosswalks,parking lots, narrow streets, etc.). Often, pedestrians use noise todetect when a car is moving and judge its relative position. Topedestrians, it is difficult to judge the movement and the relativeposition of quiet vehicles, such as electric vehicles and noise-dampenedconventional vehicles, even if the vehicle is actually moving.Additionally, various governments (e.g., city, county, perish, state,province, prefecture, country, etc.) may impose requirements forvehicles to emit a minimum amount of noise to provide acousticinformation to pedestrians while additionally having noise pollutionordinances. For example, the National Highway Traffic SafetyAdministration is developing a standard for a minimum level of noise(see, for example, NHTSA-2011-0148 and 49 C.F.R. §571) to be emitted byroad vehicles base on, in part, a standard (SAE J2889) developed by theSociety of Automotive Engineers to measure a minimum level of noiseemitted by a road vehicle.

As disclosed herein below, a vehicle includes a sound control unit thatproduces a relatively high-pitched noise at the front of the vehicle.Additionally, the sound control produces a relatively low-pitched noiseunder the vehicles, using the space between the vehicle and the roadwayas a resonance chamber. The sound control unit is communicativelycoupled to an external network to receive localized information tochange the pitch and/or intensity of the produced sounds. The localizedinformation is based on the location (e.g., coordinates provided by aglobal positioning system (GPS) receiver) of the vehicle. Additionally,the localized information may include weather information, sound-relatedlegal information, map information, and/or pedestrian information. Thesound control unit receives vehicle motion data from various electroniccontrol units (ECUs) to modify the produced sounds based on the motivestate of the vehicle. The sound control unit may, from time-to-time,connect to microphones in the vicinity around the vehicle to receivefeedback. Based on these sources, the sound unit adjusts the soundsproduced in the front and below the vehicle.

FIG. 1 is a system diagram with a vehicle 100 operating in accordancewith the teachings of this disclosure. The vehicle 100 may be anoise-dampened conventional vehicle, a hybrid vehicle, an electricvehicle, or a fuel cell vehicle, etc. The vehicle 100 may benon-autonomous, semi-autonomous, or autonomous. The vehicle 100 includesparts related to mobility, such as a powertrain with an engine or anelectric motor, a transmission, a suspension, a driveshaft, and/orwheels, etc. In the illustrated example, the vehicle 100 includes anon-board communications platform 102, an infotainment system 104,electronic control units 106, sensors 108, sound generators 110 a and110 b, a microphone 112, and a sound control unit 114.

The on-board communications platform 102 includes wired or wirelessnetwork interfaces to enable communication with external networks 116and/or mobile devices 118 (e.g., smart phones, smart watches, tablets,etc.). The on-board communications platform 102 also includes hardware(e.g., processors, memory, storage, antenna, etc.) and software tocontrol the wired or wireless network interfaces. In the illustratedexample, the on-board communications platform 102 includes a cellularmodem 120 and/or a dedicated short range communication (DSRC)transceiver 122. Additionally, the on-board communications platform 102includes a wireless local area network (WLAN) controller 124, anauxiliary port 126, and a GPS receiver 128. The cellular modem 120includes controllers for standards-based networks (e.g., Global Systemfor Mobile Communications (GSM), Universal Mobile TelecommunicationsSystem (UMTS), Long Term Evolution (LTE), Code Division Multiple Access(CDMA), WiMAX (IEEE 802.16m); and Wireless Gigabit (IEEE 802.11ad),etc.). The WLAN controller 124 includes controllers to connect to themobile device 118 via wireless local area networks, such as a Wi-Fi®controller (including IEEE 802.11 a/b/g/n/ac/p or others), a Bluetooth®controller (based on the Bluetooth® Core Specification maintained by theBluetooth Special Interest Group), and/or a ZigBee® controller (IEEE802.15.4), and/or a Near Field Communication (NFC) controller, etc. Theauxiliary port 126 provides hardware and software for a wired connectionwith the mobile device 118. The auxiliary port 126 includes one or moreports (e.g., a universal serial bus (USB) port, a Lightning® connectorport, etc.) in which to plug a cable (not shown) between the mobiledevice 118 and the auxiliary port 126.

The example DSRC transceiver 122 includes antenna(s), radio(s) andsoftware to broadcast messages and to establish direct connectionsbetween the vehicle 100 and DSRC nodes 130 installed on infrastructure132 (e.g., traffic signals, traffic control boxes, lamp posts, tunnels,bridges, buildings, etc), DSRC-enabled mobile devices 134 carried bypedestrians 136, and/or DSRC transceivers of other vehicles. DSRC is awireless communication protocol or system, mainly meant fortransportation, operating in a 5.9 GHz spectrum band. More informationon the DSRC network and how the network may communicate with vehiclehardware and software is available in the U.S. Department ofTransportation's Core June 2011 System Requirements Specification (SyRS)report (available athttp://www.its.dot.gov/meetings/pdf/CoreSystem_SE_SyRS_RevA%20(2011-06-13).pdf),which is hereby incorporated by reference in its entirety along with allof the documents referenced on pages 11 to 14 of the SyRS report. DSRCsystems may be installed on vehicles and along roadsides oninfrastructure. DSRC systems incorporating infrastructure information isknown as a “roadside” system. DSRC may be combined with othertechnologies, such as Global Position System (GPS), Visual LightCommunications (VLC), Cellular Communications, and short range radar,facilitating the vehicles communicating their position, speed, heading,relative position to other objects and to exchange information withother vehicles or external computer systems. DSRC systems can beintegrated with other systems such as mobile phones.

Currently, the DSRC network is identified under the DSRC abbreviation orname. However, other names are sometimes used, usually related to aConnected Vehicle program or the like. Most of these systems are eitherpure DSRC or a variation of the IEEE 802.11 wireless standard. The termDSRC will be used throughout herein. However, besides the pure DSRCsystem it is also meant to cover dedicated wireless communicationsystems between cars and roadside infrastructure system, which areintegrated with GPS and are based on an IEEE 802.11 protocol forwireless local area networks (such as, 802.11p, etc.).

The infotainment system 104 provides an interface between the mobiledevice 118 and/or an occupant (e.g., driver, passenger, etc.) of thevehicle 100, and the sound control unit 114. In the illustrated example,the infotainment system 104 communicatively couples to the mobile device118 (e.g., via the auxiliary port 126, via the WLAN controller 124,etc.). The infotainment system 104 facilitates the occupant selecting(e.g., via the mobile device 118, via the infotainment head unit 202 ofFIG. 2 below, etc.) a sound profile. The sound profile provides abaseline waveform (e.g., pitch, amplitude, etc.) for the sound controlunit to use to generate noise external to the vehicle 100. Additionally,the sound profile may contain sounds features such as a set of harmonicsand can control the attack time, decay time, sustain time, release time(ADSR) envelope. Additionally, in some examples, the sound profile alsoprovides a waveform to be played by the internal sound system of thevehicle 100 based on the speed of the vehicle 100. For example, when amuscle car mode is selected, the sound control unit 114 produces soundslike a Ford® Mustang®. As another examples, when a forest mode isselected, the sound control unit 114 produces sounds compatible withcampground surroundings.

The ECUs 106 monitor and control the subsystems of the vehicle 100. TheECUs 106 communicate properties (such as, status of the ECU 106, sensorreadings, control state, error and diagnostic codes, etc.) and/orreceive requests from other ECUs 106 via the vehicle data buses (e.g.,the vehicle data bus 204 of FIG. 2 below). Some vehicles 100 may haveseventy or more ECUs 106 located in various locations around the vehicle100 communicatively coupled by the vehicle data buses. The ECUs 106 arediscrete sets of electronics that include their own circuit(s) (such asintegrated circuits, microprocessors, memory, storage, etc.) andfirmware, sensors, actuators, and/or mounting hardware. The ECUs 106include may include, for example, a transmission control, anengine/motor control, a steering control, and a brake control. Theexample ECUs 106 provide vehicle motion data for the sound control unit114 to control the sound emitted by the sound generators 110 a and 110 bto reflect the driving condition of the vehicle (e.g., the vehicle isidling, the vehicle is slowing, the vehicle is accelerating, etc.).

The sensors 108 may be arranged in and around the vehicle 100 in anysuitable fashion. The sensors 108 may include camera(s), sonar, RADAR,LiDAR, ultrasonic sensors, optical sensors, or infrared devicesconfigured to measure properties around the exterior of the vehicle 100.Additionally, some sensors 108 may be mounted inside the passengercompartment of the vehicle 100 or in the body of the vehicle 100 (suchas, the engine compartment, the wheel wells, etc.) to measure propertiesin the interior of the vehicle 100. For example, such sensors 108 mayinclude accelerometers, odometers, tachometers, pitch and yaw sensors,wheel speed sensors, cameras, microphones, and thermistors, tirepressure sensors, biometric sensors, etc. The sensors 108 measure astate of the vehicle 100 (e.g., idling, accelerating, decelerating,moving, stopped, reversing, speed, etc.).

The vehicle 100 includes at least two sound generators 110 a and 110 b.The sound generators 110 a and 110 b communicatively couple to the soundcontrol unit 114. One of the sound generators 110 a is located at thefront of the vehicle 100. The front sound generator 110 a produces ahigh frequency sound (e.g., 1280 Hz to 20,480 Hz). Another one of thesound generators 110 b is located under the vehicle 100 and is directedto use the space between the vehicle 100 and the roadway as a resonancechamber. The lower sound generator 110 b produces a low frequency sound(e.g., 20 Hz to 1280 Hz). The microphone 112 senses the sounds producedby the lower sound generator 110 b. The microphone 112 provides feedbackto the sound control unit 114. As described in FIG. 3 below, the soundgenerators 110 a and 110 b produce sounds in response to signalsreceived from the sound control unit 114.

The sound control unit 114 (sometimes referred to herein as a “soundcontroller”) generates signals to produce sounds using the soundgenerators 110 a and 110 b. The sound control unit 114 generates a soundmodel based on localized data and vehicle motion data received via theinfotainment system 104. In some examples, the vehicle motion dataincludes information from the ECUs 106 and/or the sensors 108, such as(a) the position of the transmission, (b) the revolutions per minute(RPM) of the engine or motor, (c) the steering wheel position, (d) thevehicle speed, (e) the weather (e.g., rain), (f) position of thethrottle, and/or (g) the position of the brake pedal. Additionally, insome examples, the localized data includes information provided byservers on external network(s) 116, such as (a) map data, (b) trafficdata, (c) pedestrian density data, (d) laws and regulations (e.g., soundordinances, etc.), (e) time of day, and/or (f) an event calendar. Insome examples, the input includes external feedback information, such as(a) microphones 138 coupled to the DSRC nodes 130 installed oninfrastructure 132 and/or the DSRC-enabled mobile devices 134 carried bythe pedestrians 136. The sound control unit 114 uses the inputs tomodify a standard sound profile or a baseline sound profile selected byan occupant of the vehicle 100.

In some examples, the sound control unit 114 dynamically changes thesound profile based on the vehicle motion data from the ECUs 106 and/orthe sensors 108. For example, the sound control unit 114 may changeamplitudes of certain frequency ranges based on the revolutions perminute (RPM) of the engine or motor. As another example, the soundcontrol unit 114 may change the amplitudes of certain frequency rangesbased on a measured braking force and/or a measured acceleration.Additionally, compression of the sound can make the sound appear to begreater without increasing the size of the sounds generators 110 a and110 b. In some examples, the sound control unit 114 dynamically controlsthe sound profile based on the location of the vehicle 100. In some suchexamples, the sound control unit 114 amplifies the noise produced by thesound generators 110 a and 110 b when the vehicle 100 is in the vicinityof a crosswalk.

The sound control unit 114 includes an adaptive filter 140 to generatesignals for the sound generators 110 a and 110 b. The adaptive filter140 generates the signals based on the sound profile and feedback fromthe microphone 112. Within the adaptive filter 140, a low-frequencyfilter may be linked or combined with a high-frequency filter to matchthe phase of the sound between the two sound ranges produced by thefront sound generator 110 a and the lower sound generator 110 brespectively. In such a manner, overtone series are created such thatthe human auditory system can localize the sound using both amplitudeand phase differentials. The microphone 112 senses the sound generatedby the lower sound generator 110 b and changed by the resonance chambereffect. The adaptive filter 140 modifies the signal to the lower soundgenerator 110 b until the sound matches the sound profile.

FIG. 2 is a block diagram of electrical components 200 of the vehicle ofFIG. 1. In the illustrated example, the electrical components 200includes the onboard communication platform 102, an infotainment headunit 202, ECUs 106, the sensors 108, the sound generators 110 a and 110b, the microphone 112, the sound control unit 114, and a vehicle databus 204.

The infotainment head unit 202 provides an interface between the vehicle100 and a user (e.g., a driver, a passenger, etc.). The infotainmenthead unit 202 includes digital and/or analog interfaces (e.g., inputdevices and output devices) to receive input from the user(s) anddisplay information. The input devices may include, for example, acontrol knob, an instrument panel, a digital camera for image captureand/or visual command recognition, a touch screen, an audio input device(e.g., cabin microphone), buttons, or a touchpad. The output devices mayinclude instrument cluster outputs (e.g., dials, lighting devices),actuators, a heads-up display, a center console display (e.g., a liquidcrystal display (“LCD”), an organic light emitting diode (“OLED”)display, a flat panel display, a solid state display, etc.), and/orspeakers. In the illustrated example, the infotainment head unit 202includes the infotainment system 104. In some examples, the infotainmenthead unit 202 displays the infotainment system 104 on the center consoledisplay. Additionally, the inputs of the infotainment head unit 202control the infotainment system 104.

In the illustrated example of FIG. 2, the sound control unit 114includes a processor or controller 206, memory 208, and the adaptivefilter 140. The processor or controller 206 may be any suitableprocessing device or set of processing devices such as, but not limitedto: a microprocessor, a microcontroller-based platform, a suitableintegrated circuit, one or more application-specific integrated circuits(ASICs), or one or more field programmable gate arrays (FPGAs). Thememory 208 may be volatile memory (e.g., RAM, which can includenon-volatile RAM, magnetic RAM, ferroelectric RAM, and any othersuitable forms); non-volatile memory (e.g., disk memory, FLASH memory,EPROMs, EEPROMs, memristor-based non-volatile solid-state memory, etc.),unalterable memory (e.g., EPROMs), read-only memory, and/or ahigh-capacity storage device (e.g., a hard drive, a solid state drive,etc.). In some examples, the memory 208 includes multiple kinds ofmemory, particularly volatile memory and non-volatile memory. In someexamples, the memory 208 includes sound profiles that may be selected bya user.

The memory 208 is a computer readable medium on which one or more setsof instructions, such as the software for operating the methods of thepresent disclosure can be embedded. The instructions may embody one ormore of the methods or logic as described herein. In a particularembodiment, the instructions may reside completely, or at leastpartially, within any one or more of the memory 208, the computerreadable medium, and/or within the processor 206 during execution of theinstructions.

The terms “non-transitory computer-readable medium” and“computer-readable medium” should be understood to include a singlemedium or multiple media, such as a centralized or distributed database,and/or associated caches and servers that store one or more sets ofinstructions. The terms “non-transitory computer-readable medium” and“computer-readable medium” also include any tangible medium that iscapable of storing, encoding or carrying a set of instructions forexecution by a processor, or that cause a system to perform any one ormore of the methods or operations disclosed herein. As used herein, theterm “computer readable medium” is expressly defined to include any typeof computer readable storage device and/or storage disk and to excludepropagating signals.

The adaptive filter 140 transforms the sound profile maintained by thesound control unit 114 into signals sent to the sound generators 110 aand 110 b. The adaptive filter 140 generates a signal based on the soundprofile. The adaptive filter 140 receives feedback of the soundgenerated by the sound generators 110 a and 110 b. In some examples, thefeedback is received from the microphone 112. Additionally, oralternatively, in some examples, the feedback is received (e.g., via theDSRC transceiver 122) from microphones of the DSRC nodes 130 attached toinfrastructure 132 and/or microphones of the DSRC-enabled mobile devices134. For example, based on the location of the vehicle 100, the soundcontrol unit 114 may request feedback from devices (e.g., the DSRC nodes130, the DSRC-enabled mobile devices 134, etc.) in the vicinity of thevehicle 100. The adaptive filter 140 compares the received feedback tothe sound profile and corrects the signal sent to the sound generators110 a and 110 b.

The vehicle data bus 204 communicatively couples the ECUs 106 and thesensors 108. In some examples, the vehicle data bus 204 includes one ormore data buses. The vehicle data bus 204 may be implemented inaccordance with a controller area network (CAN) bus protocol as definedby International Standards Organization (ISO) 11898-1, a Media OrientedSystems Transport (MOST) bus protocol, a CAN flexible data (CAN-FD) busprotocol (ISO 11898-7) and/a K-line bus protocol (ISO 9141 and ISO14230-1), and/or an Ethernet™ bus protocol IEEE 802.3 (2002 onwards),etc. In some examples, the ECUs 106 and sensors 108 are organized onseparate data buses to manage, for example, safety, data congestion,data management, etc. For example, the sensitive ECUs 106 (e.g., thebrake control unit, the engine control unit, etc.) may be on a separatebus from the other ECUs 106 (e.g., the body control unit, theinfotainment head unit 202, etc.).

FIG. 3 illustrates an example sound generator 110. The front soundgenerator 110 a and the lower sound generator 110 b are examples of thesound generator 300. In the illustrated example, the sound generator 110includes a sound transducer 302, a body 304, and one or more adjustabletone holes 306. The sound transducer 302 includes an electro-magnet anda diaphragm. Alternatively, in some examples, the sound transducer 302includes a whistle and diaphragm, an electric motor and an impactor, orany other suitable electro-mechanical devices. In the illustratedexample, the body 304 is a spiral resonance chamber. The length of thebody 304 affects the tone of the sound generator 110. For example, thebody 304 of the front sound generator 110 a is relatively short, and thebody of the lower sound generator 110 b is relatively long. Theadjustable tone holes 306 are controlled (e.g., by a solenoid by thesound control unit 114. The adjustable tone holes 306 open and close toadjust the pitch of the sound generator 110.

FIG. 4 is a flowchart of an example method to generate sounds to warnpedestrians (e.g., the pedestrian 136 of FIG. 1). Initially, at block402, the sound control unit 114 determines whether a sound profile hasbeen selected (e.g., via the mobile device 118 communicatively coupledto the infotainment system 104, via the infotainment head unit 202,etc.). If a sound profile has been selected, at block 404, the soundcontrol unit 114 retrieves the selected sound profile (e.g., from thememory 208). Otherwise, if one of the sound profiles has not beenselected, at block 406, the sound control unit 114 retrieves the defaultsound profile. At block 408, the sound control unit 114 determineswhether localized legal information is available for the municipality inwhich the vehicle 100 is located. If the localized legal information isavailable, the method continues at block 410. Otherwise, if thelocalized legal information is not available, the method continues atblock 412.

At block 410, the sound control unit 114 modifies the sound profilebased on the localized legal information. For example, a local ordinancemay specify minimum and/or maximum amplitudes for vehicle noise. Atblock 412, the sound control unit 114 modifies the sound profile basedon an environmental context. For example, the sound control unit 114 maymodify the sound profile due to environmental noise (such as trafficnoises, weather-related noises, etc.). At block 414, the sound controlunit 114 modifies the sound profile based on the driving context of thevehicle 100. The driving contexts include the speed of the vehicles, theposition of the brake pedal, the position of the acceleration pedal, thelocation of the vehicle 100 relative to a crosswalk, traffic density,and/or pedestrian density, etc. For example, the sound control unit 114may modify the pitch of the sound generated by the sound generators 110a and 110 b in response to the vehicle slowing down (e.g.,high-frequency tones fade, etc.).

At block 416, the sound control unit 114, via the adaptive filter 140,generates a signal for the sound generators 110 a and 110 b based on themodified sound profile. At block 418, the sound control unit 114, viathe microphone 112, collects feedback of the sounds produced by thesound generators 110 a and 110 b. In some examples, the sound controlunit 114 also collects feedback from microphones 138 attached to DSRCnodes 130 attached to infrastructure 132 and/or microphone ofDSRC-enabled mobile devices 134 carries by pedestrians 136 via the DSRCtransceiver 122. At block 420, the sound control unit 114 determineswhether to modify the signals driving the sound generators 110 a and 110b based on the feedback gathered at block 418. If the sound control unit114 determines to modify the signals driving the sound generators 110 aand 110 b based on the feedback, the method continues at block 422.Otherwise, if the sound control unit 114 determines not to the signalsdriving the sound generators 110 a and 110 b based on the feedback, themethod returns to block 412. At block 422, the sound control unit 114generates and applies corrective factors to the signals driving thesound generators 110 a and 110 b so that the sounds produced by thesound generators 110 a and 110 b approximates the target sound in thesound profile.

The flowchart of FIG. 4 is a method that may be implemented by machinereadable instructions that comprise one or more programs that, whenexecuted by a processor (such as the processor 206 of FIG. 2), cause thevehicle 100 to implement the sound control unit 114 of FIGS. 1 and 2.Further, although the example program(s) is/are described with referenceto the flowcharts illustrated in FIG. 4, many other methods ofimplementing the example the sound control unit 114 may alternatively beused. For example, the order of execution of the blocks may be changed,and/or some of the blocks described may be changed, eliminated, orcombined.

In this application, the use of the disjunctive is intended to includethe conjunctive. The use of definite or indefinite articles is notintended to indicate cardinality. In particular, a reference to “the”object or “a” and “an” object is intended to denote also one of apossible plurality of such objects. Further, the conjunction “or” may beused to convey features that are simultaneously present instead ofmutually exclusive alternatives. In other words, the conjunction “or”should be understood to include “and/or”. The terms “includes,”“including,” and “include” are inclusive and have the same scope as“comprises,” “comprising,” and “comprise” respectively.

The above-described embodiments, and particularly any “preferred”embodiments, are possible examples of implementations and merely setforth for a clear understanding of the principles of the invention. Manyvariations and modifications may be made to the above-describedembodiment(s) without substantially departing from the spirit andprinciples of the techniques described herein. All modifications areintended to be included herein within the scope of this disclosure andprotected by the following claims.

1. A method for a vehicle to provide acoustic information topedestrians, the method comprising: producing a first sound at a firstfrequency range from a first sound generator located at a front of thevehicle; producing a second sound at a second frequency range from asecond sound generator located under the vehicle; adjusting, by aprocessor, acoustic characteristics of the first and second sounds basedon vehicle motion data; and adjusting at least one of the first sound orthe second sound based on feedback collected from infrastructure nodes.2. The method of claim 1, including adjusting the acousticcharacteristics of the first and second sounds based on at least one ofgovernment regulation data, weather data, or ambient noise data. 3.(canceled)
 4. The method of claim 1, including adjusting the secondsound based on feedback collected from a microphone positioned under thevehicle.
 5. The method of claim 1, including adjusting at least one ofthe first sound or the second sound based on feedback collected frommobile devices in a vicinity external to the vehicle.
 6. (canceled) 7.An apparatus to a vehicle to provide acoustic information to pedestrianscomprising: a first sound generator positioned at a front of thevehicle; a second sound generator positioned under the vehicle; and asound controller to: produce a first sound from the first soundgenerator; produce a second sound from the second sound generator;adjust acoustic characteristics of the first and second sounds based onvehicle motion data; and adjust at least one of the first sound or thesecond sound based on feedback collected from mobile devices in avicinity external to the vehicle.
 8. The apparatus of claim 7, whereinthe first sound is in a first frequency range, and the second sound isin a second frequency range, the second frequency range different fromthe first frequency range.
 9. The apparatus of claim 7, wherein thefirst sound and the second sound are an overtone series.
 10. Theapparatus of claim 7, wherein the sound controller is to adjust theacoustic characteristics of the first and second sounds based on atleast one of government regulation data, weather data, or ambient noisedata.
 11. (canceled)
 12. The apparatus of claim 7, wherein the soundcontroller is to adjust the second sound based on first feedbackcollected from a microphone positioned under the vehicle.
 13. (canceled)14. The apparatus of claim 12, wherein the sound controller is to adjustat least one of the first sound or the second sound based on secondfeedback collected from infrastructure nodes.
 15. A non-transitorycomputer readable medium comprising instructions that, when executed,cause a vehicle to: produce a first sound at a first frequency rangefrom a first sound generator located at a front of the vehicle; producea second sound at a second frequency range from a second sound generatorlocated under the vehicle; and adjust acoustic characteristics of thefirst and second sounds based on vehicle motion data and feedbackcollected from infrastructure nodes.